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    61.
    发明专利
    未知

    公开(公告)号：DE59907371D1

    公开(公告)日：2003-11-20

    申请号：DE59907371

    申请日：1999-01-14

    Applicant: ABB RESEARCH LTD

    Inventor： BOHNERT KLAUS ,  BRAENDLE HUBERT

    IPC: G01D5/353 ,  G01L1/24 ,  G01L11/02 ,  G02B6/02 ,  G02B6/10 ,  H01S3/06 ,  G02B6/16

    Abstract: The invention relates to a frequency-coded fiber laser pressure sensor (1) which is especially suitable for measuring isotropic pressures in oil wells. The sensor principle provided for in the invention is based on the fact that in a fiber laser (2) doped with Er a monomode or bimodal sensor fiber (5, 5a, 5b) is positioned whose pressure-related birefraction results in a frequency shift and beat frequencies between the orthogonal linear polarisation modes x, y or the spatial modes LP01 and LP11 line. The beat frequencies are easily measured using a frequency counter (19). Temperature-related variations in birefraction are compensated in a differential arrangement of two sensor fiber segments (5a, 5b). Fiber-integrated Bragg gratings (4a, 4b) with low bandwidths (0.2 nm) are especially suitable as laser end reflectors. The pressure sensor (1) is characterized by a large measurement range (100 Mpa) and a high triggering capacity , (kPa), is readily multiplexed and can be housed in a very compact, light-weight and robust pressure-resistant housing (25).

    HIGH-RESOLUTION FIBRE LASER SENSOR
    62.
    发明专利
    HIGH-RESOLUTION FIBRE LASER SENSOR 未知

    公开(公告)号：AU2003218858A1

    公开(公告)日：2003-11-17

    申请号：AU2003218858

    申请日：2003-04-29

    Applicant: ABB RESEARCH LTD

    Inventor： BOHNERT KLAUS ,  HAROUD KARIM ,  FRANK ANDREAS ,  BRANDLE HUBERT

    IPC: G01D5/34 ,  G01D5/353 ,  G01L1/24 ,  G01L9/00 ,  G01L11/02 ,  H01S3/067 ,  H01S3/08 ,  H01S3/098

    Abstract: High resolution fiber-laser sensor has a double refracting first end reflector (11), a second end reflector (12), a laser amplifying fiber (13), a sensor fiber and mode coupling means (15). A number of longitudinal modes are generated in the fiber laser and interaction of a measurement valve (M) causes a change in the double refraction for the two orthogonal light polarizations. The change causes a change in beat frequency of the laser emission. The first end reflector is detuned with respect to the second end reflector. An Independent claim is made for a method for measurement of a measurement value using an optically pumped fiber laser, whereby detuned end reflectors are used and at least a signal is detected and evaluated with said signal composed of exactly two longitudinal modes based on their polarization and transverse spatial structure.

    64.
    发明专利
    未知

    公开(公告)号：BR9916626A

    公开(公告)日：2001-10-30

    申请号：BR9916626

    申请日：1999-12-16

    Applicant: ABB RESEARCH LTD

    Inventor： BOHNERT KLAUS ,  BRAENDLE HUBERT

    IPC: G01F1/44 ,  G01L1/24 ,  G01L11/02

    Abstract: The present invention relates to a fiber laser pressure sensor 1 which is suitable in particular for measuring differential pressures and flow velocities v1 in oil boreholes. The fiber laser 2 according to the invention comprises two sensor fiber segments 5a, 5b subjected to different pressure loading, in which segments a birefringence proportional to the differential pressure DELTAp=p1-p2, and consequently a beat frequency, is induced between the polarization modes or spatial modes in the fiber laser 2. Exemplary embodiments with polarimetric monomode fibers 5a, 5b and/or with elliptical two-mode fibers 5a, 5b are specified. Furthermore, pressure-resistant multichamber sensor housings 25 and wavelength division multiplex arrangements are disclosed for the fiber laser pressure sensor 1. One advantage is that the pressure signal is wavelength-coded and thus highly insensitive to interference. It can be read out directly fiber-optically over large distances between the passively optical sensor head 1 and the optoelectronic measuring device 12, 17. One application concerns the measurement of a flow velocity v1 with the aid of a Venturi tube 23.

    66.
    发明专利
    未知

    公开(公告)号：BR9908314A

    公开(公告)日：2000-11-07

    申请号：BR9908314

    申请日：1999-02-12

    Applicant: ABB RESEARCH LTD

    Inventor： BOHNERT KLAUS ,  BRAENDLE HUBERT ,  BODOR PATRICK

    IPC: G01L9/00 ,  G01L11/02

    Abstract: The subject-matter of the present invention is a wavelength-coded fiber Bragg grating pressure sensor 1 which is suitable, in particular, for use in the case of high pressures and temperatures in oil drill holes. The sensor principle according to the invention is based on the fact that the hydrostatic pressure of a liquid or gaseous medium 11 is converted with the aid of a transducer 1 into a longitudinal fiber elongation or fiber compression. The transducer 1 comprises a measuring or pressure cylinder 7a which exchanges pressure with the medium 11, and a reference cylinder 7b which is shielded from the medium 11 or oppositely pressure-loaded. Temperature-compensated transducers 1 with a temperature-independent Bragg wavelength lambdB can be realized by introducing a suitable temperature dependence of the mechanical prestressing of the pressure sensor fiber 3 by selecting the materials, lengths and arrangements of the fiber holder supports 5a, 5b. A fiber Bragg grating temperature sensor 19, 20 can be provided, in addition. Also specified are transducers 1 with other cylinder arrangements 7a, 7b, and a wavelength-division multiplex configuration with several transducers 1.

    67.
    发明专利
    未知

    公开(公告)号：NO20004276L

    公开(公告)日：2000-10-18

    申请号：NO20004276

    申请日：2000-08-25

    Applicant: ABB RESEARCH LTD

    Inventor： BOHNERT KLAUS ,  BRONDLE HUBERT ,  BODOR PATRICK

    IPC: G01L9/00 ,  G01L11/02 ,  E21B47/06

    Abstract: The subject-matter of the present invention is a wavelength-coded fiber Bragg grating pressure sensor 1 which is suitable, in particular, for use in the case of high pressures and temperatures in oil drill holes. The sensor principle according to the invention is based on the fact that the hydrostatic pressure of a liquid or gaseous medium 11 is converted with the aid of a transducer 1 into a longitudinal fiber elongation or fiber compression. The transducer 1 comprises a measuring or pressure cylinder 7a which exchanges pressure with the medium 11, and a reference cylinder 7b which is shielded from the medium 11 or oppositely pressure-loaded. Temperature-compensated transducers 1 with a temperature-independent Bragg wavelength lambdB can be realized by introducing a suitable temperature dependence of the mechanical prestressing of the pressure sensor fiber 3 by selecting the materials, lengths and arrangements of the fiber holder supports 5a, 5b. A fiber Bragg grating temperature sensor 19, 20 can be provided, in addition. Also specified are transducers 1 with other cylinder arrangements 7a, 7b, and a wavelength-division multiplex configuration with several transducers 1.

    69.
    发明专利
    未知

    公开(公告)号：NO20003406L

    公开(公告)日：2000-08-22

    申请号：NO20003406

    申请日：2000-06-29

    Applicant: ABB RESEARCH LTD

    Inventor： BOHNERT KLAUS ,  BRONDLE HUBERT

    IPC: G01D5/353 ,  G01L1/24 ,  G01L11/02 ,  G02B6/02 ,  G02B6/10 ,  H01S3/06 ,  G02B6/16

    Abstract: The invention relates to a frequency-coded fiber laser pressure sensor (1) which is especially suitable for measuring isotropic pressures in oil wells. The sensor principle provided for in the invention is based on the fact that in a fiber laser (2) doped with Er a monomode or bimodal sensor fiber (5, 5a, 5b) is positioned whose pressure-related birefraction results in a frequency shift and beat frequencies between the orthogonal linear polarisation modes x, y or the spatial modes LP01 and LP11 line. The beat frequencies are easily measured using a frequency counter (19). Temperature-related variations in birefraction are compensated in a differential arrangement of two sensor fiber segments (5a, 5b). Fiber-integrated Bragg gratings (4a, 4b) with low bandwidths (0.2 nm) are especially suitable as laser end reflectors. The pressure sensor (1) is characterized by a large measurement range (100 Mpa) and a high triggering capacity , (kPa), is readily multiplexed and can be housed in a very compact, light-weight and robust pressure-resistant housing (25).

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